It's documented in VFP8 help under Behavior Changes Since Visual FoxPro 7.0 and INFO: SQL SELECT Behavior Changes in Visual FoxPro 8.0 mskb #813361.

>I have just installed VFP 8.0. In testing a VFP6 application under VFP8 none of my SQL Select statements run, in local Views or prg's. I get the error SQL: Group By clause is missing or invalid. Using the View Wizard the following SQL was generated:
>
>SELECT Table1.nbr, Table1.state, Table1.name, COUNT(Table1.state);
> FROM VFPTEST!TABLE1;
> GROUP BY Table1.state;
> ORDER BY Table1.state
>
>This code worked fine under VFP6
>
>Has anyone else encountered this problem and resolved it?
>
>Werner Henn